Telephone release-insuring means.



T. G, MARTIN. TELEPHONE RELEASE INSURIN G MEANS. FILED ULY 6, 1908.

APPLICATION Patented 001;. 27, 1914 2 SHEETS-SHEET 1.

T, a, MARTIN. TELEPHONE RELEASE INSUBING MEANS.

APPLICATION FILED JULY 6, 1908.

Patsnted 0012221914.

2 3HEETS-SHEET 2.

TALBOT Q. MARTIN, OF CHICAGO; ILLINOIS,

PANY, OF CHICAGO, ILLINOIS,

ASSIGNOB TO AUTOMATIC ELECTRIC GOM- A CORPORATION OF ILLINOIS.

TELEPHONE BZELEASE-INSUBING MEANS.

1,115,324. Specification of Letters 2mm. t t Oct 7 1914 Applicationfiled July 6, 1908. Serial No. 442,212.

the operator is able to extend connection from a manual subscribers lineto trunk-line 55 conductors V which lead to an automatic central stationand terminate in the firstselector switch D. Also, in connection withthe trunk-line jack there is shown an alarm circuit for signaling theoperator in the event that the plu isremoved from the T all whom it mayconcern Be it known that I, Tensor G. MAR'rIN, a citizen of the UnitedStates of America, andv resident of Chicago, Cook county, 1.111- 5 nois,have invented a certain new and useful Improvement in TelephoneRelease-Insuring Means, of which the following is a specificat-ion.

My invention relates to telephone systems in which a manual switchboardoperator 1s given control of automatic trunk selectors and connectors,or other automatic switchlng machines, for extending connection in thedirection of the called subscriber in response to the request of thecalling subscriber. In systems of this kind the operators are providedwith cord plugs for insertion in the jacks of the trunk-lines leading tothe automatic switching apparatus, and also with means for releasingsaid switching apparatus after the subscribers are through using theconnection. \Nith this arrangement it has been found that the operatorsoccasionally remove the plugs or pull down the con nections and forgetto release the automatic switches, thereby leaving the same ofi normal.Obviously, this is undesirable, as in order to'obtain the fullefficiency of apparatus of this kind, the automatic switches should bereturned to normal as soon as they are'no longer needed for maintainingthe connection between calling and called subscribers.

The object of my invention is, therefore, the provision of an alarmapparatus which will tend to prevent the operators from taking down theconnections without releasing the automatic switches--tliat is to say,which will prompt them to release the automatic switches each time thata connection is taken down at the manual board from which the saidswitches are controllable.

The nature and advantages of my invention will, however, hereinaftermore fully appear. I

Inthe accompanying drawings Figure 1 represents diagrammatically theequipment comprised in a manual central station, in a system embodyingthe principles of my invention. The line conductors of the subscr'iberssubstation A terminate in a drop and jack. An operators trunkcord-circuit is shown at C." By means of this cord-circuit =19 and 20.which, when mircmt through an alarmb ll 21 mmmonjo trunk-line-jack witout releasing the automatic exchange connection.- Fig. 2 representsdlagrammatically a connector switch D, At D there is represented afirst-selector switchallotted to the line of the substation A. p

A represents a well-known type of manual substation consisting of thereceiver 2, switch-hook 3, transmitter 4,' primary and secondarywindings 5 and 6, respectively, of the induction coil 7 and a localbattery 8.

At C (Fig. 1) is shown the operators answer ng plug 23, the clearing-outdrop relay 24, listening key 25, calling plug 26, ringing key 27,automatic calling device 28 and the operators telephone set 29. At D isshown a modified form of a selector switch of the type disclosed inUnited States Letters Patent No. 815,321, granted March 13, 1906, toKeith, Erickson & Erickson. Said switch is equipped with the usual coilsand relays, such as the vertlcal and rotary line relays 30 and 31,respectlvely, the vertical magnet 32 and the rotary magnet 33. As iscustomary, the rotary line relay controls the, side switch Wipers 34,35, 36 and 37 by the operation of the private magnet 38, which latter inturn controls the release magnet 39, under certain conditions, by theaction of its armature upon the private magnet springs. A back-releaserelay 40 enables the switch to be released after the side switch haspassed to the third position. The vertical magnet operates to raise theshaft line wipers 41 and 42 and the private wiper 43, while the ,rotarymagnet operates to place said wipers in contact with an unoccupiedtrunk-line Y leading to another selector, or to a connector switch ashere shown at D (Fi '2), The trunk line leading from the jac 6.5 to theselector D is provided with. an individual alarm coil 18, and withoperating armatures attracted, close a a number of trunks. A smallbattery 22 is provided for furnishing operating current for the relaysand alarm signals of a group of trunks. Said connector is of the generali type of local battery connector disclosed in United States LettersPatent No. 815,176, granted March 13, 1906, to Keith, Erickson &Erickson. It is also equipped, for operating, with vertical and rotaryline relays 44 and 45. The vertical line relay controls at differenttimes the vertical magnet 46, the rotary magnet 47 and the ringer relay48. The vertical magnet operates to raise the shaft wipers 49, 50 and51, the rotary magnet to place them in contact with the normal lines ofthe called subscriber, and

the'ringerrelay to throw ringing current.

At D is shown the individual first-selector of the called subscriber, amodified form of the selector shown at D.

My invention has special reference to the signaling mechanism, withcircuits, as represented in Fig. 1. The signal is designed to operate assoon as the operator withdraws the.answering plug from the jack 65, andcontinues in operation until the automatic central station switchesemployed in establishing a connection from the manual board arereleased. The method of operation is best shown by the process of makinga call. Upon taking the receiver 2 from the hook 3 and operating thegenerator 9, the subscribcr at station A sends an energizing currentthrough the line drop relay 16 over the following path: Starting fromcontact point- 14 said circuit passes through the generator 9 over theupper side of the line 1], througl'i the spring 60, contact point 61,through the line drop relay 16, over the sleeve side of the line 10 tothe armature 13 and back to the contact point 14. The line drop relay 16energizing for a moment pulls up the armature 1 7 which, acting on catchspring, 62, releases the drop This drop in turn closes an alarm circuit(not fully shown), notifying the operator that a connection is desired.The operator immediately inserts the plug 23 in the line jack 64 andthrows in the listening key Upon learning the connection desired, thecalling plug 26 is inserted into the line jack 65, which is connectedwith the trunk-line leading to a first-selector, as shown at D. By

the line of the desired subscriber,

means; of the calling device 28 the operator then automatically makesconnection with and by grounding the vertical line throws current on thecalledline.

Assuming that the number of 'the automatic station called is 220, andthat the calling plug 26 is connected with a trunk-line leading to afirst-selector, the operator, after throwing the key 25, grounds thevertical line twice for the first digit of the called number by pressingthe push-button 98,

ringing I thereby causing the spring 99 to make contact with the groundspring 100. Following this, one impulse is imparted to the rotary lineby pressing the push-button 101 once, thus causing the spring 102 inlike manner to make momentary contact with the ground spring 100. Inthis way two ground impulses are sent over the vertical line 66,followed by one impulse over the rotary line- 67, these lines normallyleading to the vertical and rotarv line relays 30 and 31, respectively,of the selector D. The vertical relay, energized once for each impulseover the vertical line, causes the same number of impulses to beimparted to the vertical magnet 32 by the action of the spring 68 beingcarried into contact with the ground spring 69 by the armature of theline relay 30.

' The vertical magnet raises the shaft wipers 41, 42 and 43 two steps,corresponding to the number of impulses (2). The single rotary impulsewhich follows every series of vertical impulses then energizes therotary relay 31. This relay, closing contact between the spring 70 andthe ground spring 69, energizes the private magnet 38 whic in turnreleases the side switch to second position. As soon as the side switchwiper 36 passes to the contact point 71, an energizing circuit is closedthrough the rotary magnet resulting in the rotation of the shaft wipers41, 42 and 43 to the first contact or trunloline leading to ,aconnector, and in the release of the side switch to third position.Should the first trunk leading to'a connector be occupied, the shaftwiper will be rotated to the next contact, and so "on until .anun-'occup-ied trunk is found. This is owing to the fact that agroundjpotential isthrown upon a private trunk-line which is occupied.Consequently, when the rivate wiper as, for instance, 43 of the sogrounded contact yvhile the side switch is in second position, anenergizing circuit is closed through the private magnet through the sideswitch wiper 37. The private magnet 38 (which we have seen is energizedin the process of bringing the rotary ma net into operation) isimmediately reenergized by the new energizing circuit arising from abusy trunk-line, and consequently retains the side switch in secondposition, thereby ector D strikes a hasintaiinng the net. Theintermittent operaticn of 5. cl rotary magnet, due to the action of therotary armature in separating two' springs and mcmentarilybreaking theenergizing circuit, continues to operate the shaft wipers until thecircuit through the private magnet is hroken, when the private wiperpasses a vacant trunk. WVhen this occurs the side switch immediatelypasses to third position, and the trunk-line conductors are joined to aconnector switch shown at l) in 2. The operator now, on pushing thebuttons for the second'digit of the called number, operates the verticaland rotary line relays of the connector, which results in raising theshaft wipers 49, 50 and 51 two steps, in releasing the side-switch tosecend position. In the case of the connector, however, after the shaftwipers have been raised by the action of the line relay 44 in closingcircuit through the vertical magnet 46, the side switch is released tosecond positicn only. As before, the side switch is controlled by theactionof the rotary line relay 45 in closing the energizing circuitthrough the private magnet 56. hen the side switch wiper passes to thecontact point 72 the rotary magnet 47 is brought under the control ofthe operator through the medium oi the vertical line relay 44.Consequently, on pushing the calling button for the last digit,acorresponding number of impulses is imparted to the rotary magnet,after which the succeeding imlfulseover the rotary line results inreleasing the side switch to third position. In case, however. that thecalled line is busy, the so-called busy-reiease is accomplished in theusual manner while the side switch is still in second position. When theside switch Wipers 52 and 53 pass to third position, the connection ofthe calling line with the called line is completed. The operator, thengrounding the vertical line by operating the push-button 28, energizesthe ringing relay 48 and throws current from the generator F; out on'the called line. 'This' ringing current passes irmn one side of thegenerator over the conductor 103 through the springs 194 and 105,through'the side switch contact point 108, line wiper 49, 1 theconductor 109 to the switch-hook u e switch-hook to the spring a thecalling bell 112, condenser conductor 114, line wiper 50, I it 115, sideswitch' Wiper 53, through the springs 106 and 107, over the I 116 to theother side of the gencalled subscriber in response receiver from theswitch-hook, by causing the spring 117 to :make conrh the spring 118,and the spring 119 1 120, thus completing the i energizing circuitthrough usual localbattery circuit necessary for conversation.

When the private wiper 51 of the connector D engages the private normaltrunk,

a circuit. is clsed in a well-known manner through the bridge-cut-ofi'relay 121 of the called selector. This relay, upon energizing, causesthe springs 122, 123 and 124 to separate, thus depriving the line relays125 and 126 of battery current, and making it impossible for thesubscriber at substation A to operate his selector until the connector Dhas been released. Should the subscriber at substation A desire torelease the connector D he .can do so, in the well-known manner, byfirst turning his dial, thus causingithe cooperating ground springs 127and 128 to make contact, and then, by hanging'up his receiver, groundboth line conductors simultaneously. In this-manner the back-releaserelays 58 and 59 hereinbefore mentioned are energlzed, an'd anenerglzmgcircuit is in turn closed through the release magnet 57,

releasing the connector D in the well-known manner. The bridge-cut-ofirelay 121 immediately deenergizes, placing the springs 122, 123 and 124in contact, thereby restoring battery connections to the vertical androtary relays 125 and 126. The substation A (Fig. 1) having beenconnected with substation A in the manner described, conversation may becarried on over the conductors shown by the heavy lines in Figs. 1 and2. I

After the completion of a call the release is effected by the operatorin the following manner: The calling subscriber hangs up the.

receiver, and by operating the generator causes current to pass throughthe clearingout relay 24. This circuit starting at contact point 14passes through the generator 9, tip side of the line 11 to the spring 60of the line jack 64, to the tip side of the answering plug 23, throughthe clearing-out relay 24 back over the sleeve side of said answeringplug to the line conductor 10, and through the armature 13 to thecontact 14.

. The clearing-out relay thus energized by the operation of thegenerator pulls up the armature 73,t-hcreby releasing the drop 74 andsignaling the operator that th conversation, is completed. The operatorthen withdraws the calling plug 26, presses the release button 7 5 andgrounds both sides of the line, effecting the release of all of theautomanic switches and their restoration to norma The circuit closed bythe push-button 75 extends on one side from ground G over the conductor66, side switch wiper 34, through the vertical line wiper 41, over theconductor 76 to the vertical line relay 44, through said relay to thebattery lead 77, thence through battery B to ground G. The

circuit on the other side extends from ground G over the conductor 67,through the side switch wiper 35, rotary line wiper 42, over theconductor 7 9 t the rotary line relay 15, through said relay to thebattery. lead 77, thence through battery B to ground G. The vertical androtary line relays, upon energizing simultaneously, close thefront-release springs 80 and 81 in contact.

the calling plug 26 enters the jack 65, preparatory to making a call bythe operator, a circuit is closed through the alarm relay 18. Thecircuit extends from the positive main side of the battery 22 over theconductor 8 1, through the springs and 86, over the conductor 87, overthe conductor 88 and through the winding of alarm relay 18 to thenegative side of the battery 22. This alarm relay in energizing attractsthe armatures 19 and 20, and another circuit is thereby closed throughthe alarm relay. This circuit extends from the positive side of. thebattery 22 over the conductor 8 1,

through the contact springs 90 and 91, over the conductor 92, throughthe contact 93 to the alarm relay armature 20, through the Winding ofsaid relay to the negative side of v the battery 22. The first circuitthrough the alarm relay 18 is destroyed and a new circuit is completedthrough the alarm hell 21 as soon as the calling plug is withdrawn. Thealarm relay continues energized by the second circuit through it, justtraced, and maintains the armatures 19 and 20 in their attractedpositions.

Thecircuit through the alarm bell 21 extends from the positive side ofthe battery 22 over the conductor 84:, through the spring contacts 85and-94:, over the conductor 95 to the armature 19, through the contactpoint 96, through the alarm bell 21, overthe conductor 97 to thenegative side of the battery 22. Thus, as soon as the calling plug 26 iswithdrawn the operators attention is attracted by the ringing of thealarm bell 21, which continues until the release button hasbeenpressed,and the circuit throng. the alarm relay is thereby broken by theseparation of thecontact springs 90 and 91. Upon the deenergization ofthe alarm rela' 18 the armatures' 19 and 20 drop back, t ereby alsocausing another break in said circuit through the relay. Consequently,upon the release button 7 5 being released, and the contact springs 90and 91 again closing, no energizing circuit passes through the alarmrelay 18. By the operation of this alarm system, therefore, the

operator is prevented from leaving the automatic switches ofi' normal,since upon withdrawing the calling plug the alarm bell will ring untilthe release push-button 75 is op erated to release the automaticswitching apparatus brought into service.

From the foregoing it will be seen that I rovide an alarm whereby theoperator will e given a signal whenever she takes down the connectionwithout releasingthat is to say, whenever she withdraws the cord plugand leaves the automatic switches in their operated condition. Thepreferred method of operation is as follows: \Vhen the subscribers arethrough talking and the operator gets the disconnect signal, she thenwithdraws the plug from the trunk-line leading to the first-selector D,and at the same time presses the button 75, thus taking down theconnection and releasing at the same time. In this way the twooperations are accomplished without ringing the bell 21, which, ofcourse, is desirable. On the other hand, when the'operator hears thebell ring, then she understands that in taking down the connection sheforgot to release the automatic switches. This she cando by pressing thebutton 7 5 in the manner previously explained.

W'hat I claim as my invention is 1.f' In a telephone system, anautomatic switch for extending connection in the direction of the calledsubscriber, means including a plug and jack by which a manualswitchboardoperator extends connection tosaid switch to control the same, a si alat said switchboard, automatic means or operating said signal if theplug is withdrawn from the jack and the automatic switch is notreleased, and'mean's for releasing the switch in response to the saidsignal. I

2. In a telephone system, an automatic trunking switch for extendin inthe direction of the calle subscriber, means including a plug and 'sickfor extending connection to said switc to control the same, meanscontrolled by -the manual switchboard operator for extending connectionfrom said switch to the called subscribers line,- means by which theoperator releases the said automatic switch and the means for extendingconnection therefrom, a signal at said switchboard, and automatic meansfor operating said signal if the plug is withdrawn from the jack withoutreleas- In a telephone syttem, the combination of an automatic switch, aplug and jack by connection lishing a connection between said lines,-said .trollcd and opened by the actuation of said key-switch, a signalhaving a circuit closed at one point by the energizing of said relay andclosed at another point therein by the withdrawal of the plug from thejack, whereby the said signal is operated if the operator withdraws theplug from the jack without releasing the automatic'switch.

4. In a telephone system having manual switchboards, the combination ofan automatic switch, a trunk-line leading thereto, means for. connectinga calling subscriber with said trunkdine, means by which a manualswitchboard operator controls said antomatic switch to extend theconnection in the direction of the called subscriber, means by which-thesaid operatormay release the said automatic switch, a signal at saidswitchboard, and automatic means for operating said signal whenever theconnection to the automatic switch is taken down or broken withoutreleasing said switch.

5. In a telephone system,'a calling and a called subscribers line, meansfor establish:

ing a connection between said lines, said means including a manualswitchboard provided with an alarm signal, an automatic switch, means atsaid manual switchboard for controlling said automatic switch to extendconnection in the direction of the called subscriber, means at saidmanual switchboard 'for releasing said switch after the subscribers arethrough talking, and automatic means at said manual switchboard foroperating said signal whenever the operator disconnects the twosubscribers without releasing said switch.

6. The combination, in a telephone we change trunking system, of acalling and a called subscribers line, means for estabmeans including anautomatic switch for extending connection in the direction of the calledsubscribers' line, means by which a person may control said switch, saidswitch having one motion to select a group and another motion to find anidle line in the predetermined group, a signal, automatic means foroperating said signal if the switchis not restored when the connectionis broken between the two subscribers lines, and means for releasing theswitch in response to the said signal.

7. The combination, in a telephone exchange trunking system, of anautomatic switch for extendin connection in the direction of the calledsu scribers line, means including a plug and jack by which a manualswitchboard operator extends connection to said switch to control thesame, said switch having one motion to select a group and another motionto find an idle line in the predetermined group, a signal, automaticmeans for operating said signal if the plug is withdrawn from the jackand the automatic switch is not released, and means for releasmg theswitch in response to the said signal;

8. The combination, in a telephone exchange trunking system, of anautomatic switch, a line circuit, means for controlling said switch overthe line circuit, said switch having one motion to select a group andanother motion to find an idle line in the predetermined group, meansfor initiatingthe release of said switch over the'line circuit, andautomatic means whereby the person who thus controls or releases saidswitch is given a signal if the said switch is not released after anattempt has been made to initiate the release over the line circuit.

9. The combination, in a telephone ex- I change trunking system, of anautomatic switch, a trunk line leading thereto, means for connecting acalling subscribers line with said trunk line, means by which the manualswitchboard operator controls said automatic switch to extend theconnection in the direction of the called subscribers line, said switchhaving one motion to select a group and another motion-to find an idleline in the predetermined group, means by which the said operator mayrelease the said automatic switch, a signal at said switchboard, andautomatic means for operating said signal whenever the connection to theautomatic switch is taken down or broken without releasing said switch.

10. The combination, in a telephone exchange trunking system, of anautomatic switch, means for extending a calling subscribers' linethereto, said switch having one motion to select a group and anothermotion to find an idle linein the predetermined group, means forreleasing said switch, a signal, and automatic means for operating saidsignal whenever the subscribers line is disconnected from said switchwithout releasing the same.

11. A telephone exchange trunking system comprising an automatic switch,a plug.

connection to' Lime; 1

and closed at another point therein by the Signed by me at Chicago, Cookcounty, 10 withdrawal of the plug from the jack, Illinois, this 2nd dayof July, 1908.

whereby the said signal is operated if the operator withdraws the plugfrom the jack TALBOT Gr. MARTIN. without releasing the automatic switch,the

said automatic switch having one motion to Witnesses:

select a group and another motion to auto- EDWARD D. FALES,

matically select an idle trunk in the pre-' ARTHUR B. SPERRY.

determined group. i

